Manufacture of flanged tubes



N.c.DooLi-:Y

MANUFACTURE oF FLANGED TUBES `Filed Aug. s, 1939 heretofore has when'the amount of upset in any single opera- Patented Deefso, 41941 1 ENT OFFICE y" MANUFACTURE oF FLANGED TUBES y, Detroit, Mich.,A assignor Norman Clovice Doole toAmeric'an Metal Products 00,.

Detroit, Mich.

Application August s, 1939, serial Nol 283,911

4 claims. (o1. zia- 156) cold shuts.` In addition, the new niethod is simple of the metal during the upsetting operation so tiontha'n in prior methods, without resultingin i Y cold shuts or other imperfections'in the metal.

of anged tubes, such as erations wherein a quantityof metal is gathered to thicken the end of the videv the metalfor the ange. According to common practice, the tube is initially progressively until external diameter.` 4 The upsetting of metal tubes as `practiced not produced satisfactory results One feature of the present invention, there-fore,

resides in the provision of tube and vthereby pro- I as to provide on the tube an which is strong and durable.

According to the new method, the tube is initially thickened at a. series of upsetting opera.-

as 4great as the lexternal diameter of the main body of the the external'diameter of the main body of the tube. The thickened and expanded portion of the tube is then conned in a space with'a clearance around'the outside of this portion, and while it is at a forging temperature it is subjected to a to `build up thefiange. l

With this method, an upset of 100% may beobtained in a single operation without producing cold shuts. metal at one" upsetting operation, a thickened portion V is ,50 a novel method of forming' a iiange on a metal tube, by the .practice of which an upset substantially in excess of may be obtained in a single operation without causing imperfections in the metal, such as formed having its greater thickness intermediate resists any substan- For a better understanding of the invention,

in application and results in a controlled'ow` integralVV flange one end in any suitable manf ations.

k"it is of gradually increasing reference may be had to the following detailed description taken in conjunction with the accompanyingl drawing, in which Fig. l is a longitudinal, sectional view of one end 'of a metal subsequent to the preliminary upsetting and expanding operations but prior to the main upsetting operation, and

Figs. 2, 3 and 4 are longitudinal, sectional views of part of the thickened portion of the tube illustrating different stages of the main upsetting operation wherein an upset of approximately 100% is obtained.

In the practice of subjected to preliminary upsetting operations which gather metal from one end of the tube and consequently thicken the tube, as shown at I'I in Fig. l. However, prior to the main upsetting operation, panded to form a socket I8. According to the preferred method, the thickened-part l1 isexpanded from the end of the tube inwardly to a point I9 which is at least half the distance to the inner end 2d of the thickened part, and the latter is made of a length equal to or ternal diameter of the main body 2l of the tube. The socket It may be tion by which the metal is gathered to form the I1 or it may be'formed by inin the end of the tube after the metal has been gathered in the preliminary operpreferably expanded so that the internal diameter of the end of the tube is equal to or greater than the external diameter of the main body 2i. 'Ihe socket It could be formed with its major wall parallel to tube, but, as shown, diameter from its inner end 'ISI to the outer endof the tube. 'I'he initial upsetting and expanding operations are preferably lcorrelated s o that the thickened part I1 prior' to the described has an external `the corresponding radius of the mainv body 2i by at least the thickness of the main body. Also, l prefer to form manner.that it gradually increases in external diameter from its inner end 2li to a point substantially in radial alignment with the inner end ls of the socket. Y v

The tube'in the form shown in Fig', 1 isjy'placed in a diev 22 which provides a substantial clearance '23 around the outside of the thickened portion, as shown in Fig. 2. The tube issecured against longitudinal movement in the die and, while at a forging temperature'is subjected to a compressive blow by a punch 24 which fits closely in the tube and is formed with a shoulder 25 which strikes the 'end ofthe tube. `As the thickened part I1 shortens under the action of the punch,-

metal' is displaced-into the vclearance 23 so as to n increase the external diameter of the thickened portion. Since the portion 25 ofthe inner wall of the socket near the end of the tube is disposed outwardly at least as farfas theiouter wall of the main body 21 the compressive force tending to buckle the' thickened part I1 is off-set outend 20 of the thickened `portion so that itis less effective as' a buckling force, and there i's a tendency for the metal above an imaginary line between points 20 and 25 to slide back over the metal below this imaginary line, as shown in Fig. 3. Also, since the part I1 is thickest intermediate its ends, it offers the greatest resistance to buckling at the region the thickened part of the tube is exless than the exformed in the same opera-` Vwhere buckling would normally occur. While the part I1 may buckle a slight amount, as illustrated in Fig. 3, previous expansion of the end of the "tube in forming the socket I8 causes the outer the new method, the tube is and sticks'to the punch, it maintains In either case, the thickened end I1 is punch is moved ,a short the thickened part I1 in such a wall of the thickened portion to lie considerably closer to the inner wall 22 of the. die than would otherwise be the case, and, as a result, this inner wall limits the buckling to a negligiblefa'mount. When the upsetting proceeds to the stage where the thickened portion engages the outer wall 22'` y of the clearance space,

as shown at 26 in Fig. 3, continued movement of the punch causes metal `to now inwardly into thespace 2l in the socket and outwardly into the space 28 outside the socket and also forces .metal back into the corner Z5 of the clearance space, to form the flange 3l).

Since the part of the which is first contacted by the punch is chilled radial position'throughout the upsetting-operation. The relatively thick, intermediate-portion of the part I1' tends to resist expansion more eiectively than the end portions of this part which are thinner and therefore more thoroughly heated and at a higher temperature. Accord'-4 ingly, while the intermediate portion of the par-t I1 is buckling slightly, upsetting or thickening of the stock near the ends of" the'part I1 is occurring so as to fill the corners ofthe clear-.- ance space. It will be observed that after the intermediate portion 2t of the part I1 first contacts the wall 22' of the clearance space, this intermediate portion is moved back parallel to the axis of the tube to'av position near the rear end of the thickened part, as shown in Fig.4. Also, during the slight buckling `of the partv I1, the intermediate portion 3l thereof adjacent the distance outwardly,but after the part 26 contacts the outer wall 22' of the clearance space, further expansion of the metal by the punch depresses the portion 3| and causes it to reengage the punch. Thus, the metal is caused .to flowV in al controlled-manner such that the corners of the clearance space are filled without any appreciable buckling of the thickened part Il.

By the practice of thel new method, upsets as high as 100% may be obtained in a single operation with entirely satisfactory results, In many instances, therefore, at least one upsetting operation may be saved over the number of operations required in the conventional practice wherein each upset is relativelysmall. vfince the flange formed by the new method is free of cold shuts and similar imperfections, it has all the strength and durability of similarly shaped flanges formed in accordance with the more expensive conventional practice requiring a greater. number vof upsetting operations.

I claim:

1. A method. of forming a ilange on a metal tube, which' comprises gathering metal 'from ,one

a thickened portion gradually increasing in thickness from the inner end thereof to a point intermediate itsends, expanding the thickened portion to form a socket gradually decreasing in internal diameter from the outer end of said thickened portion to a point intermediate the ends thereof, confining the expanded portion within a space-l with a substantial clearance around the outside of said portion whereby a substantial length of the socket wall radially outwardly against the wall of said clearthickened portion I1 v the' same l ance by subjecting the outer end of the expanded portion to axial compression while securing said end against radial movement.

2. A method of forming a ilange on a metal tube, which comprises gathering metal from one end of the tube to form a thickened portion gradually increasing in thickness 'from the inner end thereof toa point intermediate its ends, expending the thickened portion from the outer end thereof to apoint at leasthalf the distance to the opposite inner end of said thickened portion to form a socket having an internal diameter at the end of the tube at least as great as the external diameter of the main body of the tube, conilning the expanded portion within Va. space with a substantial clearance around the outside of said portion whereby a substantial length or the socket wall is unsupported around the outv side, and buckling the intermediate part of the expanded portion radially outwardly against the wall of said clearance by subjecting the outer end oi' the expanded portion to axial compression while securing said-end against radial movement.

3. Amethod of `forming a flange on a metal tube, which comprises gathering metal from one end of the tube to form a thickened portion gradually increasing in thickness from the inner end thereof to a point intermediate its endsI expanding the thickened portion from the outer end thereof to a point at least half the dis ce to the opposite inner end Vof said thickened portion to form a socket of a length substantially greater than the thickness of the socket wall. confining the expanded portion within a space with a sub'- stantial clearance around the outside of said portion whereby a substantial length of the socket wall is unsupported around the outside, and buckling the intermediate part of the expanded portion radially outwardly against the wall of said clearance by subjecting the outer end of the expanded portion to axial compression while securingwsaid end against radial movement.

4. A method of forming a flange on a metal I tube, which comprises gathering metal from one end of the tube to form a thickened portion gradually increasing in thickness from the inner end thereof to a point intermediate its ends,

expanding the thickened portion from the outer end thereof to a point at least half the distance to the opposite inner end of said thickened portion, confining the expanded portion within a space with a substantial clearance around the outside of said portion whereby a substantial length of the socket wail is unsupported around theoutside, and buckling the intermediate part of the expanded portion radially outwardly against the wall of said clearance by subjecting the outer end of the expanded portion to axial compression while securing said end against radial movement.

NORMAN CLOVICE DOOLEY 

